(1) Field of the Invention
This invention relates to pipe joints, and more particularly to a joint for connecting pipes of synthetic resin material such as nylon or of a soft metal such as copper which serve as a conduit for fluids.
(2) Description of the Prior Art
There has been known in the art a push-in type pipe joint which can connect a pipe with a suitable strength simply by inserting one end of the pipe axially into a bore of a joint casing which, for instance, accommodates an annular plate or a ring tiltably for locking engagement with the inserted end of the pipe. With this type of pipe joint, the pipe is easily inserted into the joint by guiding the connecting end of the pipe concentrically with the opening of the annular plate or ring which, once the pipe is inserted, is tilted relative to the axis of the pipe by the action of a spring to hold the circumference of the pipe clampingly with its inner peripheral portions. The annular plate or ring is tilted in such a direction that its inner peripheral portions will bite on the circomference of the pipe with a greater force if the pipe is pulled outward or in a disconnecting direction, securely holding the pipe in the connected position.
Such pipe joints thus far have been required to employ a tilting plate or ring which has an inside diameter sensibly larger than the outside diameter of the pipe in order to facilitate pipe insertion through the tiltable plate or ring. In addition, the tiltable plate or ring is required to have a thickness greater than a certain value in order to ensure secure biting action of the inner peripheral edge portions of the disc or ring. Consequently, the disc or ring has to be tilted through a relatively large angle to perform the above-mentioned clamping function. These requirements are very disadvantageous to the compactness of the joint. Any pipe joint is desired to have a compact construction since otherwise it would unduly bulge out when mounted to connect a pipe to hydraulic equipments such as valves and piston-cylinders. A bulky joint is susceptible to damages by hitting upon nearby structures and could be an obstacle to operations or piping work in a narrow space. With regard to the compactness, the above-mentioned conventional pipe joint has large limitations inherent to its construction.
In order to detach the pipe from the conventional joint mentioned above, a release pin which is associated with the annular plate or ring is operated to return the tilted plate or ring into the upright coaxial position, setting the pipe loose. However, this procedure is troublesome and sometimes difficult since in most cases the pipe joints employ very small release pins to cope with the outside diameters of the pipes which are generally 18 mm or less, along the circumference of the pipe.
The conventional pipe joint has another drawback in that it is relatively complicated in construction and presents problems during automatic mechanical assembling process, including the problem of biased load on the spring.
It is therefore an object of the present invention to provide a pipe joint which permits of easy connection and disconnection of a pipe without using any tool.
It is another object of the present invention to provide a pipe joint employing a radially displaceable clamp ring which is located in the pipe passage in the joint casing and provided with a sharp edge around the inner periphery thereof to clampingly bite on the circumference of a pipe when the clamp ring is pressed into an eccentric position after pipe insertion thereby automatically holding the pipe in the connected position.
It is still another object of the present invention to provide a pipe joint employing a release ring which is slidably fitted at the entrance of the pipe passage and which is easily manipulatable from outside to push the clamp ring into a concentric position thereby releasing the pipe from the clamping action of the sharp edge of the clamp ring to allow extraction of the pipe without using any tool.
It is a further object of the present invention to provide a pipe joint in which the biting action of the sharp edge becomes stronger by displacement of the clamp ring when the joint is subject to a force which tends to extract the pipe therefrom, thereby producing a greater resistance to such extracting force.
It is a further object of the present invention to provide a pipe joint of a simple and compact construction which can securely hold a pipe in the connected position simply through eccentric displacement of a clamp ring.
It is still another object of the present invention to provide a pipe joint constituted by component parts which are easily obtainable by simple operations on a press or a lathe to allow mass production at low costs.
It is a further object of the present invention to provide a pipe joint which can cope with pipes with a larger tolerance in outer diameter, as compared with the conventional counterparts.